Signal transmitting means



. March 14, 1933. E. D. McARTHUR SIGNAL TRANSMITTING MEANS Original Filed Nov.

FIELD QURRENT Fig.5.

Inventor: Elmer D. ["10 Arthur, b

' His' Attorneg,

w more Patented Mar. 14, 1933 UNITED STATES v PATENT OFFICE.

m D. HGABTEUB, OB ULADY, NEW YORK, ASSIGNOB 1'0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK SIGNAL MEANS. I

Application filed November 20, 1928, Serial R0. 820,708. Renewed October 15, 1888.

My present invention relates to signal transmitting means employing electron dischar e devices of the divided anode type and in w ch a magnetic field is reduced between the anode members; A ischarge device of this t e is disclosed in copending application, Serial No. 285,008, filed June 13, 1928, Kinjiro Okabe entitled Extra short wave generating device, and will'be described ully heremafter. Particular constructions thereof are shown in my co plication, Serial No. 389,067, filed August 28,

1929, entitled High frequency magnetron apparatus and in application, Serial No.

398,249, Kenneth C. Dewalt,-filed October 8,

1929, and entitled Electron discharge apparatus. My invention relates more particularly to discharge devices of the type indicated when used together with-circuit arrangements whereh ultra short wave oscillations are produce My invention has for one of its objects to provide means whereby oscillations produced y means of the t pe of device indicated may be efliciently m ulated accordance with desired signals. 7

The novel features which I believe to be characteristic ofmy invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further ob'ects and advantages thereof, may best be un erstood by reference to the following description taken in connection with the accompanying drawing in which .Fig. 1 re resents one embodiment of my invention; ig. 2 represents a characteristic thereof, and Fig. 3 represents a modification.

Referring to the drawing I have indicated an electron discharge device of the type'more full described in my above mentioned copen ing application, and which com rises an evacuated vessel having disposed t erein a plurality of anodes 2. These anodes are preferably curvilinear and are arranged in cylindrical formation. Extending along the axis of the cylinder formed by the anodes 2 is a heated cathode -3 which-is arranged ending apt be energizedfrom an energy source 4. Connected between the anodes 2 is an oscillatory circuit comprising inductance 5 and capacit 6. This oscillatory circuit is coupled wit any suitable load circuit 7 which ma if desired, comprise a radiating s stem. ach of the anodes issupplied with direct current potential from a source 8 which is connected between the cathode and the mid-point of the inductance 5, although of course an other suitable connection may be employed:

The electron discharge device is provided with a direct current field winding 9 which is energized from a source of direct current potential 10 through resistances 11 and 12. This field winding produces. a unidirectional magnetic flux within the discharge device an between the anodes thereof the magnetic lines of which extend parallel with the inner surface of the anodes.

If we assume that the source of potential 10 and the resistances 11 and 12 are so adjusted that a flux is produced within the discharge device of desired intensit oscillations will be roduced in the oscil atory circuit 5, 6, which oscillations are supplied to the load circuit 7. These oscillations may be of any desired frequency dependent upon the-characteristic of the oscillatory circuit. It has been found in a particular case in which inductance 5 consisted only of the inductance of the leads which extend from the anodes through the walls of the vessel and which were then connected together by acopper bar, and the capacity 6 consisted only of the capacity between t e anodes and connected leads, which anodes were of about a centimeter in diameter and of somewhat greater length, that oscillations were pro duced having a wave length of but a few centimeters. It has also been found that by properly preportioning' the circuits these oscillations may be made of ve low frequency. Frequencies as low as sixty have been produced.

The intensit of the oscillations which are produced in t e circuit 5, 6 varies with respect to the strength of the current in the field circuit in the manner shown b the curve 13 of Fig. 2 in which theintensit'y of oscillating current is plotted as ordinates and cycles a rent also increases in an approximately lin-- ear relation until a critical point is reached as represented by the top of the curve 13, at

which point oscillations entirely cease."

Thus, for example, if the device is to be utilized as a telegraphic transmitter, the resistance 11 may be so adjusted that the current flowing in the field circuit is such that the oscillations produced have desired intensity and resistance 12 will be of such a value that when short circuited as by means of a key 14, the field current will increase to a point such that no oscillations are produced. Thus by opening and closing the key 14, the production of oscillations may be interrupted in accordance with desired signals. Keying may also be effected, of course, by varying the field current from zero, or some low value, to a higher value at which oscillations of desired intensity are produced.

For telephonic communication. the intensity'of the field current should preferably be "ad usted at some value as, for example, at a value represented by the point B on t e curve 13, such that the intensity of the oscillations produced is about half of the maximum value. The resistance across the terminals of resistance 12 may thenbe varied in accordance with voice waves, as by means of a microphone connected in shunt therewith, thereby to increase and diminish the intensity of the oscillations in the circuit 5, 6 in the relation expressed by that portion of the curve 13 lym between limits re resented, for example, Iy points ,A and In this way voice modu atlon of the oscillations produced may be conveniently and eiiiciently effected.

In Fig. 3 I have shown a modification ofmy invention in which the electron discharge device comprises a plurality of pairs of anodes 2, 2, these pairs of anodes having connected therebetween oscillatory circuits 15,

p 15 respectively. In this case the load circuit 7 is associated with all of the oscillatory circuits 15, 15' and is adapted to be supiplied with high frequency current there rom.

. The oscillatory circuits 15 and 15' are tuned preferably at the same frequency and each of them cooperate with the pair of anodes to which they are connected to produce oscillations in the manner mentioned in connection with Fig. 1. .The oscillations in all of these circuits may be synchronously modulated and, hence, the oscillations in the load circuit 7 may be modulated in the manner described in connection with Fig. 1, although in Fig. 3 I have represented a key as replaced by a microphone 16. It will be understood, of course, that either of these devices may be employed.

The number of pairs of anodes employed in the modification shown in Fig. 3 may of course be increased as desired, each pair be-@ ing arranged symmetrically with respectto the cathode and all of the anodesbeing arranged preferably in cylindrical formation about the cathode. I p One of the important advantages ofthe system described resides in the fact that the high frequency power output from a transmitter employing an' electrpn discharge de- .vice of the typeindicated can be increased by electrodes. In increasing the radial dimensions of the discharge device employed it has been found that so long as the ratio between the radius of the anode cylinder and the Wldth of the slit D between adjacent anodes is kept constant the limit of frequency at which the device will operate Will not be changed. That is, the internal capacity will remain constant.

While I haveshown particular embodiments of my invention, it will of course be understood that I do not wish to be limited thereto since many modifications, both in the circuit arrangement and in the instrumentalities employed, may be made without departing from the spirit and scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure byLetters Patent of the United States, is:

1. The combination, in a high frequency v transmitter, of an electrondischarge device, having a cathode and a plurality of anodes, said anodes being symmetrically arranged with respect to the cathode and adjacent thereto, an oscillatory circuit connected between said anodes, means forproducing a unidirectional magnetic field between said anodes, said magnetic field being independent of current in said oscillating circuit, and means for varying said magnetic field in accordance with the signal to be transmitted thereby to vary the intensity of the oscillations produced in said oscillatory circuit.

2. The combination, in a high frequency transmitter, of anelectron discharge device having a cathode and a plurality of anodes, said anodes being symmetrically arranged with respect to the cathode and adjacent thereto, an oscillatory circuit comprising the inherent capacity between said anodes, and

an inductance connected between said anodes,

a field circuit for producing a magnetic field between said anodes, circuit connections cillations ceasing when the intensity of the magnetic field reaches a predetermined max site sides of said cathode,'a pluralityof oscillatory circuits, each of said oscillatory circuits including an inductance connected between a pair of said anodes and means for producing a magnetic field between each pair of said anodes whereby oscillations are excited in all of said oscillatory circuits.

4. The combination, in a high frequency generator, of an electron discharge device I having a cathode and a plurality of anodes, said anodes being arranged in pairs, the anodes of each pair being disposed symmetrically with respect to said cathode, a pluralflowing in the field circuit thereby to modulate the oscillations supplied to said load circuit.

In witness whereof, I have hereunto set my hand this 19th day of November, 1928.- ELMER D. MGARTHUR. H

ity of oscillatory circuits, each of said oscillatory circuits including-an inductance con.- nected betweena pair of said anodes, means forcproducing a magnetic field between each pair of said anodes whereby oscillations are excited in all of said oscillatory circuits, and

means for modulating the oscillations pro-- duced in all ofsaid oscillatory circuits. j

5. The combination, in a high frequency 3 V transmitter, of an electron discharge device,

having a plurality of pairs of anodes arranged in cylindrical formation, an electron emitting cathode extending along the. axis veach of said of the cylinder formed by said anodes and on opposite sides of said cathode, a plurality of oscillatory circuits, each of said oscillapairs of anodes being arranged,

tory circuits including a pair of anodes.

means for producing a magnetic field extending parallel with the inner surface of said anodes and between each air of anodes whereby oscillations are pr need in said oscillatory circuits and means for modulating the oscillations produced.

6. The combination, in a high frequency generator, of an electron discharge device having a cathode and a plurality of anodes, said anodes being arranged in pairs, the anodes of each pair being disposed on o posite sides of said cathode, a plurality 0 0scillatory circuits, each of said oscillatory circuits including an inductance connected between a pair of said anodes, means for producing a magnetic field between each pair of said anodes whereby oscillations are excit-.

ed in all of said oscillatory circuits, said means includinga normally energized field circuit, a load circuit supplied with high frequency oscillations from each of said oscillatory circuits, and means for superim signal current upon the current normally 

